It has been proposed to provide a crash detector to respond to a side impact in a motor vehicle. Typically, the crash detector incorporates a sensor which is mounted on the door or which is mounted on part of the door-frame, such as the B-pillar. The sensor may comprise an accelerometer.
When a vehicle provided with such crash detector is involved in a side impact, part of the vehicle, where the accelerometer is mounted, is deformed, and the accelerometer is exposed to a high acceleration. The crash detector incorporates means responsive to this sensed high acceleration to deploy a safety device, such as an air-bag or a seat-belt pre-tensioner.
However, it has been found that an accelerometer mounted on the door of a motor vehicle or mounted on part of the door-frame may be subjected to a high acceleration when the door of the vehicle is slammed. The high acceleration may be sufficient to cause the safety device be deployed. This is clearly disadvantageous, since it is most undesirable for the safety device to be deployed as a consequence of a door slam.
It is not, however, appropriate simply to adjust the sensitivity of the accelerometer, since in a side impact situation it is very important that the safety device is deployed, and is deployed swiftly.